CVE-2026-107353mediumCWE-1321

CVE-2026-107353: medium-severity vulnerability in ljharb traverse

traverse: set() can write to built-in prototypes via an untrusted path

Published

10Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 6.9
exploitation probability
—
observed exploitation
nono source reports it
traverse (npm) versions 0.3.6 through 0.3.9, 0.4.0 through 0.4.6, 0.5.0 through 0.5.2, and 0.6.0 through 0.6.11 allow prototype pollution through set(). When the path passed to set() crosses a primitive value, the next path segment is resolved on that primitive's built-in prototype, so an application that passes an untrusted path to set() lets an attacker add or overwrite properties of String.prototype, Number.prototype, or Boolean.prototype using plain JSON data, for example traverse({ name: 'bob' }).set(['name', '__proto__', 'polluted'], 'yes'). Object.prototype was reachable only with a non-data path segment, such as an object whose toString returns a different value on each call, or through a Proxy that accepts an assignment without storing it. This is fixed in 0.3.10, 0.4.7, 0.5.3, and 0.6.12.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Affected products
ljharb · traverse